Choi Kwang, Jeong Min Ju, Lee Seungmin, Alosaimi Ghaida, Seidel Jan, Yun Jae Sung, Noh Jun Hong
School of Civil, Environmental and Architectural Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
Department of Chemistry, Faculty of Science, Taif University, Taif 26571, Saudi Arabia.
ACS Appl Mater Interfaces. 2022 Jun 1;14(21):24341-24350. doi: 10.1021/acsami.2c03492. Epub 2022 May 20.
Mixed-halide perovskites (MHPs) have attracted attention as suitable wide-band-gap candidate materials for tandem applications owing to their facile band-gap tuning. However, when smaller bromide ions are incorporated into iodides to tune the band gap, photoinduced halide segregation occurs, which leads to voltage deficit and photoinstability. Here, we propose an original post-hot pressing (PHP) treatment that suppresses halide segregation in MHPs with a band gap of 2.0 eV. The PHP treatment reconstructs open-structured grain boundaries (GBs) as compact GBs through constrained grain growth in the in-plane direction, resulting in the inhibition of defect-mediated ion migration in GBs. The PHP-treated wide-band-gap (2.0 eV) MHP solar cells showed a high efficiency of over 11%, achieving an open-circuit voltage () of 1.35 V and improving the maintenance of the initial efficiency under the working condition at AM 1.5G. The results reveal that the management of GBs is necessary to secure the stability of wide-band-gap MHP devices in terms of halide segregation.
混合卤化物钙钛矿（MHP）因其易于调节带隙而作为串联应用中合适的宽带隙候选材料受到关注。然而，当较小的溴离子掺入碘化物中以调节带隙时，会发生光致卤化物偏析，这会导致电压损失和光不稳定性。在此，我们提出了一种原始的后热压（PHP）处理方法，该方法可抑制带隙为2.0 eV的MHP中的卤化物偏析。PHP处理通过面内方向的受限晶粒生长将开放结构的晶界（GB）重构为致密的GB，从而抑制了GB中缺陷介导的离子迁移。经PHP处理的宽带隙（2.0 eV）MHP太阳能电池显示出超过11%的高效率，开路电压（）为1.35 V，并在AM 1.5G工作条件下提高了初始效率的保持率。结果表明，为确保宽带隙MHP器件在卤化物偏析方面的稳定性，晶界管理是必要的。
